In a wireless network, TSCH technology divides the wireless bandwidth into time and frequency and wireless nodes can communicate (i.e. transmit and/or receive data) during a timeslot over a specific bandwidth (i.e. frequency channel). A Time Division Multiple Access (TDMA) schedule determines during which timeslot and over which frequency channel a node should transmit or receive data to/from its neighbours.
In the latest defined IEEE 802.15.4e standard, the mechanism of how the TSCH schedule operates in the network is defined, but it is not specified how an optimised schedule is built. It is desirable to have a scheduling method that is compliant to TSCH and work based on the IEEE 802.15.4e TSCH MAC.
Industrial applications can have different latency demands. For example, process control or monitoring applications (e.g. environmental monitoring) can be non-time critical. On the other hand, factory automation, disaster defence and safety applications etc. highly sensitive to delays. Thus, the latency and system response time of such applications is important and the Quality of Service (QoS) requirements are often in the scale of hundreds of milliseconds.
Many wireless networks have links between nodes of poor quality, resulting in a high rate of communication failure between these nodes. Furthermore, certain links between nodes may have a higher traffic demand (i.e. are required to transmit more data packets during a scheduling period). It may be advantageous for a scheduling method to account for these variations in link reliability and traffic demand when defining a schedule.
Wireless network nodes are often powered by batteries with limited capacity. As such, power efficiency should be maximised and unnecessary power usage within devices should be minimised.